diff --git a/Cargo.toml b/Cargo.toml
index 59aa718..6195c9c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,12 @@ serde_json = "1.0"
 serde_with = "1.9.1"
 time = "0.2"
 # TODO: reduce feature set to just the ones needed
-tokio = { version = "1.20", features = ["full"] }
-hyper = { version = "0.14", features = ["full"] }
+tokio = { version = "1", features = ["full"] }
+hyper = { version = "0.14.27", features = ["full"] }
 async-trait = "0.1.68"
+
+[features]
+default = ["u64_backend"]
+u32_backend = ["curve25519-dalek/u32_backend"]
+u64_backend = ["curve25519-dalek/u64_backend"]
+simd_backend = ["curve25519-dalek/simd_backend"]